Model-based analysis for kinetic complexation study of Pizda and Cu(II). Vosough, M.; Maeder, M.; Jalali-Heravi, M.; Norman, S. E. Chemistry and Chemical Engineering Research Center of Iran, Tehran, Iran. Spectrochimica Acta, Part A: Molecular and Biomolecular Spectroscopy (2008), 70A(3), 674-681. Publisher: Elsevier B.V., CODEN: SAMCAS ISSN: 1386-1425. Journal written in English. CAN 149:137412 AN 2008:705098 CAPLUS

Abstract

In the present work, the multivariate kinetic complexation of a new synthesized ligand, 1-(2''-hydroxyl cyclohexyl)-3'-[aminopropyl]-4-[3'-aminopropyl]piperazine (Pizda) and Cu2+ in 50 % ethanol-water soln. is investigated using the UV-vis stopped-flow technique and state-of-the-art multi-wavelength numerical anal. Model-based least squares fitting anal. or hard modeling is a specific part of chemometrics which is based on math. relationships for describing the measurements. Some recent developments include the incorporation of the effects of non-ideal exptl. conditions into the fitting algorithm so it can substantially simplify exptl. procedures. In this study no buffers are required because pH changes are taken into computations. Some 21 multi-wavelength kinetic measurements, taken at various initial concns. of [H+] were analyzed globally, i.e. simultaneously applying an all inclusive reaction mechanism and a common set of species spectra. Using numerical anal., the pH of the exptl. solns. was allowed to vary as a consequence of the proceeding reactions. This enabled the complete kinetic anal. of the formation and dissocn. of Cu(Pizda)n+. Here protonation equil. have been directly incorporated into the rate law, so thus variable pH values have been allowed during each measurement. Using the independently estd. stability consts. (from spectrophotometric and potentiometric measurements) for the Cu(Pizda)n+ complexes, a total of six rate consts. and one protonation const. could be elucidated. The results of the anal. incl